Well not exactly the back half but certainly the back of the ship. Generally it would be any part of a ships hull that extends behind the superstructure built above.

In the days of the the ocean liners the main hull of the ship was more easily delineated from the superstructures built on top. The ships looked more like wedding cakes building up from the hull and the "aft" and "forward" parts of the hull could be more easily seen. Today cruise ships tend to be built having a continuous vertical structure from water line to the upper most decks.

I don't know if there is an actualy definition that would describe where the aft begins as you are moving from front to back but the middle part of the ship is called "mid-ships" so perhaps its the last third of the length.

Hi Will, it's Jeff again. I just noticed from another post that you are cruising on the Victory. Not a bad choice for a first cruise. She is a beautiful ship. the biggest problem I have with her is the location of the cigar lounge directly undre the disco with an open stairwell. When I'm in relaxation mode with a cigar I don;t want to be bombarded with high energy music from above.

If you question about the aft of the ship is because you are worrided about aft vibration in your cabin then be at peace. This ship has very little vibration due to propulsion and its girth keeps the aft sway at bay.

On this ship (looking at the deck plan) I'd define the aft as any part of the ship built behind the rear stairs and elevators.

The most common use of the word "aft" is in the context of "aft of..." -- which means "behind" in land lubber's terminology. If you hear a reference to "aft elevators" or "after elevators," it simply means the elevators that are furthest aft. If something is "located aft," it's toward the rear of the ship (as opposed to "forward" or "amidships"). On most modern cruise ships, it's fair to say that the spaces aft of the after elevators are located aft, the spaces forward of the forward elevators are located forward, and the spaces the forward elevators and the after elevators are located amidships. Some ships also have amidships elevators, and others do not.

Incidentally, the naval rank of Midshipman comes from the early days of sail when the ship's officers lived in the aftercastle and the crew lived in the forecastle. The midshipman's job included relaying orders from the commissioned officers to the crew. In order to do this, they had to pass through the "waste" located amidship quite frequently -- and thus came to be known as midshipmen. To this day, a midshipman in the U. S. Navy is an officer who ranks above a warrant officer but below a chief warrant officer.